this improves data cache hits and speeds up grayscale only decoding
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Fixed Ticket636
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

* qatar/master:
  lavf: pass options from AVFormatContext to avio.
  avformat: Use avio_open2, pass the AVFormatContext interrupt_callback onwards
  avio: add avio_open2, taking an interrupt callback and options
  avio: add support for passing options to protocols.
  avio: add and use ffurl_protocol_next().
  avformat: Pass the interrupt callback on to chained muxers/demuxers
  avio: Add an AVIOInterruptCB parameter to ffurl_open/ffurl_alloc
  avformat: Use ff_check_interrupt
  avio: Add an internal utility function for checking the new interrupt callback
  avio: Add AVIOInterruptCB
  texi2html: remove stray \n
  doc: prettyfy the texi2html documentation
  swscale: handle unaligned buffers in yuv2plane1

Conflicts:
	libavformat/avformat.h
	libavformat/avio.c
	libavformat/mov.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Once we bailed out we calculate the exact iteration in which it would have happened if needed.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Use log(sqrt(mb->bailout)) instead of log(mb->bailout) because mb->bailout represent
the bailout radius squared, and then simplify the two sqrt().
This is also slightly faster.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

This allows us to remove a if() and a variable assignment.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

previous calculated pixel, this is more accurate due to the last
calculated often being farther away.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Anton Khirnov <anton@khirnov.net>